In 1995, scientists have examined human origins from the perspective of male
genetics (1, 2). Scientists have examined
a The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.gene (ZFY), which being on the One of the two sex chromosomes that determines maleness in mammals, carried and passed down from males to males.Y chromosome, is passed down only from father
to son. Thirty-eight men were chosen from all over the world (Africa, Asia,
Australia, Europe, and Northern, Central, and South America). Scientists
determined the actual genetic The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequence in each man for this The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.gene, which is 729
Two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds.base pairs long. To their surprise, all men had identical genetic The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequences(over 27,000 Two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds.base pairs analyzed). Scientists have calculated the most probable
date for the last common ancestor of modern man, given the The order of nucleotides in a DNA or RNA molecule, or the order of amino acids in a protein molecule.sequence diversity
from modern apes. Using two different models this date is either 270,000 or
27,000 years ago. However, both these models assume that the male population
during this entire period of time consisted of only 7,500 individuals. The date
estimates from these models would be significantly reduced if the male
population were higher than 7,500, which is very likely. Two separate studies
using similar techniques looked at larger pieces of the One of the two sex chromosomes that determines maleness in mammals, carried and passed down from males to males.Y chromosome, which
would reduce the uncertainty in the calculation of dates. One study examined a
The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.gene which was 2,600 Two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds.base pairs and determined a last common ancestor date of
188,000 year ago (minimum of 51,000 and maximum of 411,000 years ago) (3).
The other study used a very large piece of the One of the two sex chromosomes that determines maleness in mammals, carried and passed down from males to males.Y chromosome (18,300 Two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds.base pairs)
and calculated a last common ancestor date of modern man of 43,000 years ago
(minimum of 37,000 and maximum of 49,000 years ago) (4).

Definitions

CI (Confidence Interval)

A statistical measure of the certainty of a value. 95% CI
means that there is a 95% probability that the true result lies between the
CI values.

References

S. Paabo. 1995. The One of the two sex chromosomes that determines maleness in mammals, carried and passed down from males to males.Y chromosome and the origin of all
of us (men). Science 268: 1141.

R.L. Dorit, H. Akashi, W. Gilbert. 1995. Absence of
A common variation in the sequence of DNA among individuals of a species or race.polymorphism at the ZFY The place on a chromosome where a specific gene is located, a kind of address for the gene.locus on the human One of the two sex chromosomes that determines maleness in mammals, carried and passed down from males to males.Y chromosome. Science 268:
1183.

Whitfield, L.S., J.E. Suston, and P.N. Goodfellow. 1995.
Sequence variation of the human One of the two sex chromosomes that determines maleness in mammals, carried and passed down from males to males.Y chromosome. Nature 378: 379-380.

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Last Modified June 21, 2006